Beer or Cider Base

ABSTRACT

A method for preparing an aromatic beverage is as follows. The method includes subjecting a fermented beverage to a first filtration step including nanofiltration or ultrafiltration to obtain a retentate fraction and a permeate fraction including alcohol and volatile flavour components. Then, the method includes subjecting the permeate fraction including alcohol and volatile flavour components to a second filtration step of reverse osmosis to obtain a base liquid of at least 2% ABV. Combining the base liquid with exogenous aromas thereby obtains the aromatic beverage. Desirable fermented beverages are a beer or a cider.

TECHNICAL FIELD

The present invention concerns a method for preparing a beveragecomprising a malt-based or cider-based liquid and an exogenouscomponent. In particular, the invention concerns a method wherein thefirst step involves a subjecting a fermented beverage to a firstfiltration step to obtain a permeate fraction that is subsequentlysubjected to a second filtration step to obtain a base liquid comprisinga majority of the ethanol content of the fermented beverage andsubsequently adding an exogenous component to the base liquid therebyobtaining a desired aromatic beverage.

BACKGROUND OF THE INVENTION

Beer derived beverages are gaining more interest rapidly as these allowfurther diversification of tastes and beverage design, yet still basedon ethanol obtained by natural fermentation processes.

Key in the production of such beer derived beverages is obtaining ataste-neutral ethanol comprising base liquid whereto aromas of choicecan be added. The taste-neutral ethanol comprising base is ideally easyand cost-efficient to produce.

It is know to obtain an ethanol enriched fraction from beer for thepurpose of producing beer concentrates. U.S. Pat. No. 4,265,920 and U.S.Pat. No. 4,532,140 teach two-step methods for obtaining a high-alcoholbeer concentrate that can be reconstituted to beers of normal alcoholcontent. The method of U.S. Pat. No. 4,265,920 comprises a firstdistillation step to separate ethanol and volatile aroma components fromthe retentate comprising the rest of the beer components, which isfollowed by a second step comprising a rather costlyfreeze-concentration procedure to concentrate the retentate from thefirst step. Finally, the distilled ethanol from step 1 is combined withthe freeze-concentrated retentate from step 2, resulting in the finalethanol-enriched beer concentrate. The method of U.S. Pat. No.4,532,140, on the other hand, in the first step subjects beer toultrafiltration to obtain a concentrated retentate and an aqueouspermeate that is then, in the second step subjected to reverse osmosisto concentrate ethanol and volatile compounds; lastly, the alcoholfraction from step 2 is pulled with the retentate from step 1 to obtainthe final beer concentrate.

Although at least some of the above described methods provide a generalapproach for concentrating beer including its alcohol content they focuson retaining as much as possible of the original beer components withthe exception of water, rather than on obtaining a liquid fractioncomprising a majority of the original alcohol content and purified frommost non-volatile aromas, while maintaining a high throughput andminimizing alcohol losses.

The present invention provides a method for producing a beveragecomprising a malt-based liquid and an exogenous component, wherein themalt-based liquid concerns a naturally alcohol containing malt-basedliquid having an alcohol content of 5 ABV or higher. These and otheradvantages of the present invention are presented in continuation.

SUMMARY OF THE INVENTION

The present invention is defined in the appended independent claims.Preferred embodiments are defined in the dependent claims. Inparticular, the present invention concerns a method for preparing anaromatic beverage, the method comprising the steps of:

-   -   a) Subjecting a fermented beverage (1) to a first filtration        step comprising nanofiltration (A) or ultrafiltration to obtain        a retentate fraction (2) and a permeate fraction comprising        alcohol and volatile flavour components (3);    -   b) Subjecting the permeate fraction comprising alcohol and        volatile flavour components to a next filtration step comprising        reverse osmosis, to obtain a base liquid comprising at least 2        ABV;    -   c) Combining the base liquid from b) with exogenous aromas        thereby obtaining the aromatic beverage.

Preferably, the fermented beverage is a beer or cider, such as a beer orcider having an alcohol concentration comprised between 2-16% ABV,preferably between 2.5-10% ABV, most preferably between 3-8% ABV. Incase of a beer, the fermented beverage preferably is high gravity beerdefined as beer of original gravity of 14-25 °P or even higher.

The nanofiltration (A) in step a) preferably is is a high-pressurenanofiltration, defined as nanofiltration conducted under a pressure inthe range of 18-41 bar, preferably in the range of 20-30 bar.

The second filtration step (B) in b) preferably first comprises reverseosmosis, and then further comprises at least one additional treatment ofthe fraction comprising ethanol obtained following said reverse osmosis,said treatment comprising distillation, fractionation, or reverseosmosis.

The base liquid (4) obtained in step b) preferably comprises between2-20% ABV.

BRIEF DESCRIPTION OF THE FIGURES

For a fuller understanding of the nature of the present invention,reference is made to the following detailed description taken inconjunction with the accompanying drawings in which:

FIG. 1: shows a block diagram schematically illustrating key steps ofthe method according to the present invention. A—first concentrationstep comprising nanofiltration or ultrafiltration; B—secondconcentration step comprising reverse osmosis; C—combining of theretentate from the second concentration step with exogenous aromas.

1—beer subjected to nanofiltration; 2—retentate; 3—permeate comprisingethanol and volatile aroma components; 4—base liquid comprising at least. . . vol % of the alcohol originally present in the fermented beverage;5—leftover fraction from the second concentration step; 6—aromaticbeverage; 7 exogenous aromas.

DEFINITIONS

As used herein, the term “beer” is to be construed according to a ratherbroad definition:

-   -   “the drink obtained by fermenting from a wort, prepared with        starchy or sugary raw materials, including hop powder or hop        extracts and drinkable water. Aside from barley malt and wheat        malt, only the following may be considered for brewing, mixed        with e.g. wheat malt, starchy or sugary raw materials in which        the total quantity may not exceed 80%, preferably 40% of the        total weight of the starchy or sugary raw materials:        -   (a) maize, rice, sugar, wheat, barley and the various forms            of them.        -   (b) saccharose, converted sugar, dextrose and glucose syrup.            Although according to certain national legislations, not all            fermented malt-based beverages can be called beer, in the            context of the present invention, the term “beer” and            “fermented malt based beverage” are used herein as synonyms            and can be interchanged. It follows, that as used herein the            terms “reconstituted beer” and “reconstituted fermented malt            based beverage” are to be understood as beverages            composition-wise substantially identical to beer but            obtained by addition of the solvent, i.e. water or            carbonated water, to a previously prepared beer concentrate.

Next, as used herein, the term “cider” is to be understood as everyalcoholic beverage resulting from the fermentation of apple juice orapple juice mixed with up to 10% pear juice. This term also encompassesthe any product of this fermented apple juice further modified by addingsuch standard cider manufacturing additives as acids (citric ortartaric) and/or sugar, filtering, cooling, saturating with carbondioxide, pasteurizing, etc., which is commercialized under the termcider.

As used herein, the term “unfilterable compounds” is to be understood asreferring to all the diverse compounds comprised in any type of beer orcider, which cannot pass through a nanofiltration membrane, i.e. beercompounds having the mean size greater than 150 Da, 180 Da, or 200 Da,which is the molecular weight retention size cut-off depending on agiven nanofiltration membrane. As opposed to the “filterable compounds”comprising water, monovalent and some bivalent ions, low molecularalcohols such as ethanol, low molecular esters and a number of volatileflavour components, the unfilterable compounds mainly include sugars,mostly polysaccharides; sugar alcohols, polyphenols, pentosans, peptidesand proteins, high molecular weight alcohols, high molecular weightesters, partially multivalent ions, and many other mainly organic andhighly divergent compounds that vary depending on the beer or cidertype. Due the complexity and discrepancies between different beer orcider compositions, the collective concentration of the unfilterablecompounds is often referred to (in great simplification and withoutbeing exact) as “concentration of sugars” or “concentration of solids”and can be easily calculated from mass balance considerations takinginto account of parameters such as density, viscosity, beer rheology,original gravity or extract, real gravity or extract, degree offermentation (RDF) and/or alcohol content. In brewing practice, theconcentration of unfilterable compounds is routinely estimated fromdensity (real extract) measurement corrected for the density of themeasured ethanol amount, ethanol being the most prevalent compound ofdensity<1 g/cm³ and therefore affecting the density measurement mostsubstantially. Such measurements are well known in the art, areroutinely performed using standard beer analysing systems like AntonPaar Alcolyzer device, and thus are readily and easily performable byany person skilled in beer brewing.

The amount of components dissolved in beer can also be expressed as socalled specific gravity (relative density) or apparent specific gravity.The first one is measured as density (weight per unit volume) of beerdivided by the density of water used as a reference substance, whereasthe second one as the weight of a volume of beer to the weight of anequal volume of water. For example, a specific gravity of 1.050 (“50points”) indicates that the substance is 5% heavier than an equal volumeof water. The densities of water, and consequently also beer, vary withtemperature; therefore for both specific gravity and apparent specificgravity the measurement of the sample and the reference value is doneunder the same specified temperature and pressure conditions. Pressureis nearly always 1 atm equal to 101.325 kPa, while temperatures maydiffer depending on the choice of further systems for approximating beerdensity. Examples of such systems are two empirical scales, Plato andthe Brix scale, that are commonly used in brewing and wine industries,respectively. Both scales represent the strength of the solution aspercentage of sugar by mass; one degree Plato (abbreviated °P) or onedegree Brix (symbol °Bx) is 1 gram of sucrose in 100 grams of water.There is a difference between these units mainly due to both scalesbeing developed for solutions of sucrose at different temperatures, butit is so insignificant that they may be used virtually interchangeably.For example, beer measured at 12° Plato at 15.5° C. has the same densityas a water-sucrose solution containing 12% sucrose by mass at 15.5° C.,which is approximately equal to 12° Brix, being the same density as awater-sucrose solution containing 12% sucrose by mass at 20° C. ThePlato and Brix scales have an advantage over specific gravity in thatthey expresses the density measurement in terms of the amount offermentable materials, which is particularly useful at early stages ofbrewing. As, of course, both beer and wort are composed of more solidsthan just sucrose, it is not exact. The relationship between degreesPlato and specific gravity is not linear, but a good approximation isthat 1°P equals 4 “brewer's points” (4×0.001); thus 12° Platocorresponds to specific gravity of 1.048 [1+(12×4×0.001)].

The term “original gravity” or “original extract” refers to specificgravity as measured before fermentation, whereas the term “finalgravity” or “final extract” relates to specific gravity measured at thecompletion of fermentation. In general, gravity refers to the specificgravity of the beer at various stages in its fermentation. Initially,before alcohol production by the yeast, the specific gravity of wort(i.e. the ground malt before beer fermentation) is mostly dependent onthe amount of sucrose. Therefore, the original gravity reading at thebeginning of the fermentation can be used to determine sugar content inPlato or Brix scales. As fermentation progresses, the yeast convertsugars to carbon dioxide, ethanol, yeast biomass, and flavourcomponents. The lowering of the sugar amount and the increasing presenceof ethanol, which has appreciably lesser density than water, bothcontribute to lowering of the specific gravity of the fermenting beer.Original gravity reading compared to final gravity reading can be usedto estimate the amount of sugar consumed and thus the amount of ethanolproduced. For example, for a regular beer, original gravity could be1.050 and final gravity could be 1.010. Similarly, knowing originalgravity of a beverage and its alcohol amount can be used to estimate theamount of sugars consumed during the fermentation. The degree to whichsugar has been fermented into alcohol is expressed with the term “realdegree of fermentation” or “RDF”, and is often given as a fraction oforiginal gravity transformed into ethanol and CO₂. The RDF of beer is intheory indicative of its sweetness as beers usually have more residualsugar and thus lower RDF.

Filtration steps may involve any of the variety of techniques recognisedin the art, which allow partial or substantial separation of water fromthe beer and thus retention of most of the dissolved therein componentsin a lower than initial volume. Many of the techniques currently usedwithin the beverage industry rely on the so called membranetechnologies, which provide a cheaper alternative to conventionalheat-treatment processes and involve separation of substances into twofractions with the help of a semipermeable membrane. The factioncomprising particles smaller than the membrane pore size passes throughthe membrane and, as used herein is referred to as “permeate” or“filtrate”. Everything else retained on the feed side of the membrane asused herein is referred to as “retentate”.

Typical membrane filtration systems include for example pressure-driventechniques microfiltration, ultrafiltration, nanofiltration and reverseosmosis. As used herein, the term “microfiltration” refers to a membranefiltration technique for the retention of particles having size of 0.1to 10 μm and larger. Usually, microfiltration is a low-pressure process,typically operating at pressures ranging from 0.34-3 bar¹.Microfiltration allows separation of particles such as yeast, protozoa,large bacteria, organic and inorganic sediments etc. Then, as usedherein, the term “ultrafiltration” designates a membrane filtrationtechnique for the retention of particles having size of about 0.01 μmand larger. Ultrafiltration usually retains particles having molecularweight greater than 1000 Dalton, such as most viruses, proteins ofcertain sizes, nucleic acids, dextrins, pentosan chains etc. Typicaloperating pressures for ultrafiltration range from 0.48-10 bar. Further,as used herein the term “nanofiltration” shall be understood as amembrane filtration technique for the retention of particles having sizeof 0.001 μm to 0.01 μm and larger. Nanofiltration is capable ofretaining divalent or multivalent ions, such as divalent salts, and mostorganic compounds larger than appox. 180 Dalton, which includeoligosaccharides and many flavour compounds; while allowing water,ethanol, monovalent ions, and some organic molecules such as manyaromatic esters pass through. Operating pressures of 8-41 bar aretypical for nanofiltration. Where nanofiltration is operated under inletpressure within the upper end of this range, from 18 bar above, as usedherein, it shall be termed “high pressure nanofiltration”. Lastly, asused herein the term “reverse osmosis” shall be understood as referringto a high-pressure membrane process where the applied pressure is usedto overcome osmotic pressure. Reverse osmosis usually allows to retainparticles having size of 0.00005 μm to 0.0001 μm and larger, i.e. almostall particles and ionic species. Substances with molecular weight above50 Dalton are retained almost without exception. Operating pressures aretypically between 21 and 76 bar, but may reach up to 150 bar in specificapplications. ¹Wherein the unit bar equals 100,000 Pa, in accordancewith the definition of IUPAC, [1 Pa=1 N/m{circumflex over (2)}=1kg/m*s{circumflex over (2)} in SI units.]

Further, as used herein the term “volatile flavour components” shall beunderstood as any of the substances comprised in beer that contribute toits complex olfactory profile, said substances by their chemical naturehaving a boiling point lower than that of water. Examples of volatilebeer flavour components include but are not limited to acetaldehyde,N-propanol, ethyl acetate, isobutyl alcohol, isoamyl alcohol, isoamylacetate, ethyl hexanoate, ethyl octanoate, and many more.

For this invention “exogenous aromas” is defined as aromas or flavourcompounds not originating from or derived from the fermented beverage asfermented and subjected to the concentration steps (a) and (b) of themethod according to the invention. The “exogenous aromas” can be anykind of aroma or flavour compound either natural or synthetic notpresent in the fermented beverage as fermented and also includes aromasor flavours added to the fermented beverage subjected to theconcentration steps (a) and (b) in a post fermentation stage.

DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns a method for preparing an aromaticbeverage, the method comprising the steps of:

-   -   a) Subjecting a fermented beverage (1) to a first filtration        step comprising nanofiltration (A) or ultrafiltration to obtain        a retentate fraction (2) and a permeate fraction comprising        alcohol and volatile flavour components (3);    -   b) Subjecting the permeate fraction comprising alcohol and        volatile flavour components to a next filtration step comprising        reverse osmosis, to obtain a base liquid comprising at least 2%        ABV;    -   c) Combining the base liquid from b) with exogenous aromas        thereby obtaining the aromatic beverage.

Preferably, the fermented beverage is a beer or cider, more preferably alager type of beer having an alcohol content of 5 ABV or higher, morepreferably 8 ABV or higher.

FIG. 1 schematically illustrates general scheme of the method forpreparing an aromatic beverage according to the present invention. As afirst step, beer (1) is subjected to nanofiltration (A) through asemi-permeable membrane acting as physical barrier to passage of mostbeer components of mean molecular weight (MW)>150-200 Da, but permeableto water, majority of ethanol, monovalent salts and certain amount ofbeer flavour components. This first fraction retained on the membrane'sinflow side is termed retentate (2) and is collected, whereas thefraction comprising alcohol and volatile flavour components is termedpermeate (3) and is directed to a second filtration step (B). Accordingto the invention, the second filtration step comprises reverse osmosisand results in separation of the permeate (3) from the previousnanofiltration step (A) into two fractions: first, base liquidcomprising at least 2% ABV, which base liquid is collected andblended/mixed with exogenous aromas (7), resulting in desired aromaticbeverage (6); and, secondly, a largely aqueous leftover fraction (5),that is recycled to the inlet of the first filtration step. The desiredaromatic beverage (6) can now be consumed or further diluted with wateraccording to the desired taste profile and alcohol content.

In general, beer (1) subjected to nanofiltration (A) according to theinvention is preferably clear beer, such as a lager, that was treatedusing any regular beer clarification technique to remove yeast and mostof the other particles above 0.2 μm in diameter. Such techniques arestandard and well known in the art of beer preparation. For example,they include centrifugation, filtration through e.g. kieselguhr(diatomaceous earth) optionally preceded by centrifugation, or othertypes of standard microfiltration techniques. The beer preferably has analcohol concentration comprised between 2-16% ABV, preferably between2.5-10% ABV, most preferably between 3-8% ABV. In case of a beer, thefermented beverage preferably is high gravity beer defined as beer oforiginal gravity of 14-25 °P or even higher.

In line with the above, the present invention is based on the findingthat nanofiltration of beer, high-pressure nanofiltration in particular,not only allows to retain majority of larger beer flavour compounds inthe retentate but also provides a good throughput of alcohol to thefirst permeate, thereby allowing production of a neutral beer base inthe second filtration step. In an advantageously economical embodiment,nanofiltration is performed as a multi-stage operation, wherein theretentate is progressing from one stage to the next one while becomingmore and more concentrated and a majority of the alcohol in the beer istransferred to the permeate. It has been observed that such highconcentration potential can particularly be achieved using polymericspiral membranes in range of 150-200 Daltons or similar. Examples ofsuch membranes include thin film composite ATF (alternating tangentialfiltration, Refine Technology) membranes such as the ones currentlyavailable from DOW and Parker domnick hunter.

After the nanofiltration step, the permeate fraction is fed to thesecond filtration step b) in order to further remove tastecharacteristics of the original beer, said step comprising reverseosmosis.

In a possible embodiment of the present invention, the step b) of themethod of the invention first comprises reverse osmosis; and thenfurther comprises at least one additional treatment of the fractioncomprising ethanol, obtained following said reverse osmosis, saidtreatment comprising fractionation, preferably distillation, or reverseosmosis. In said embodiment the aqueous permeate being the fractioncomprising alcohol and volatile flavour components is first subjected toa step comprising reverse osmosis to obtain a retentate fractioncomprising alcohol at a higher concentration than before the stepcomprising reverse osmosis and leftover fraction, after which saidretentate fraction comprising alcohol is further subjected to at leastone further concentration step comprising fractionation, preferablydistillation, or reverse osmosis, to obtain a base liquid comprisingalcohol and a leftover fraction.

A in a further development of the embodiments of the present invention,a method is provided wherein the reverse osmosis is a high resolutionreverse osmosis i.e. reverse osmosis conducted under operating pressurecomprised within the range of 60-120 bar and at temperature of 0-12° C.

1. A method for preparing an aromatic beverage comprises the steps of:a) Subjecting a fermented beverage (1) to a first filtration stepcomprising nanofiltration (A) or ultrafiltration to obtain a retentatefraction (2) and a permeate fraction comprising alcohol and volatileflavour components (3); b) Subjecting the permeate fraction comprisingalcohol and volatile flavour components to a second filtration stepcomprising reverse osmosis to obtain a base liquid comprising at least2% ABV; c) Combining the base liquid from b) with exogenous aromasthereby obtaining the aromatic beverage.
 2. The method according toclaim 1, wherein the fermented beverage is a beer or a cider.
 3. Themethod according to claim 1, wherein the nanofiltration (A) in step a)is a high-pressure nanofiltration, defined as nanofiltration conductedunder a pressure in the range of 18-41 bar, preferably in the range of20-30 bar.
 4. The method according to claim 1, wherein the secondfiltration step (B) in step b) first comprises reverse osmosis, and thenfurther comprises at least one additional treatment of the fractioncomprising ethanol obtained following said reverse osmosis, saidtreatment comprising distillation, fractionation, or reverse osmosis. 5.The method according to claim 1, wherein the base liquid (4) comprisingalcohol in step b) comprises between 2-20% ABV.
 6. The method accordingto claim 1, wherein beer (1) subjected to concentration is high gravitybeer defined as beer of original gravity of 14-25 °P or even higher. 7.The method according to claim 1, wherein beer (1) subjected toconcentration comprises alcohol concentration comprised between 2-20%ABV, preferably between 2.5-20% ABV, most preferably between 8-20% ABV.8. The method according to claim 2, wherein the nanofiltration (A) instep a) is a high-pressure nanofiltration, defined as nanofiltrationconducted under a pressure in the range of 18-41 bar, preferably in therange of 20-30 bar.
 9. The method according to claim 8, wherein thesecond filtration step (B) in step b) first comprises reverse osmosis,and then further comprises at least one additional treatment of thefraction comprising ethanol obtained following said reverse osmosis,said treatment comprising distillation, fractionation, or reverseosmosis.
 10. The method according to claim 9, wherein the base liquid(4) comprising alcohol in step b) comprises between 2-20% ABV.
 11. Themethod according to claim 10, wherein beer (1) subjected toconcentration is high gravity beer defined as beer of original gravityof 14-25 °P or even higher.
 12. The method according to claim 11,wherein beer (1) subjected to concentration comprises alcoholconcentration comprised between 2-20% ABV, preferably between 2.5-20%ABV, most preferably between 8-20% ABV.